1. Field of Endeavor
The present invention relates to separator methods and apparatus and more particularly to dielectrophoretic separator methods and apparatus.
2. State of Technology
U.S. Pat. No. 5,814,200 for an apparatus for separating by dielectrophoresis by Pethig et al, patented Sep. 29, 1998, provides the following description: xe2x80x9cThe invention relates to a separator, which is particularly useful for separating cellular matter. The separator utilizes the phenomenon known as dielectrophoresis (DEP). A DEP force effects a particle suspended in a medium. The particle experiences a force in an alternating electric field. The force is proportional to, amongst other things, the electrical properties of the supporting medium and the particle and the frequency of the electric field. The separator, of the present invention, comprises a chamber (10) and a plurality of electrodes (12) disposed in the chamber (10). An electric field established across electrodes subjects some of the particles to a stronger force than others such that they are confined within the chamber. Particles which are not confined are removed from the chamber by the supporting medium which is preferably urged through the chamber. Valves (101 and 202) are provided on exhausts of the chamber. The invention is able to separate two different particles continuously.xe2x80x9d
U.S. Pat. No. 5,993,630 for a method and apparatus for fractionation using conventional dielectrophoresis and field flow fractionation, by Becker et al, patented Nov. 30, 1999, provides the following description: xe2x80x9cThe present disclosure is directed to a novel apparatus and novel methods for the separation, characterization, and manipulation of matter. In particular, the invention combines the use of frequency-dependent dielectric and conductive properties of particulate matter and solubilized matter with the properties of the suspending and transporting medium to discriminate and separate such matter. The apparatus includes a chamber having at least one electrode element and at least one inlet and one output port into which cells are introduced and removed from the chamber. Matter carried through the chamber in a fluid stream is then displaced within the fluid by a dielectrophoretic (DEP) force caused by the energized electrode. Following displacement within the fluid, matter travels through the chamber at velocities according to the velocity profile of the chamber. After the matter has transited through the chamber, it exits at the opposite end of the chamber at a characteristic position. Methods according to the invention involve using the apparatus for discriminating and separating matter for research, diagnosis of a condition, and therapeutic purposes. Examples of such methods may include separation of mixtures of cells, such as cancer cells from normal cells, separation of parasitized erythrocytes from normal erythrocytes, separation of nucleic acids, and others.xe2x80x9d
U.S. Pat. No. 5,858,192 for a method and apparatus for manipulation using spiral electrodes, by Becker et al, patented Jan. 12, 1999, provides the following description: xe2x80x9cthe present disclosure is directed to a novel apparatus and novel methods for the separation, characterization, and manipulation of matter. In particular, the invention combines the use of frequency-dependent dielectric and conductive properties of particulate matter and solubilized matter with the properties of a suspending medium to discriminate and separate such matter. The apparatus includes a chamber having at least one spiral electrode element. Matter is separated in the chamber by a dielectrophoretic (DEP) force caused by the energized electrode or electrodes.xe2x80x9d
The present invention provides a dielectrophoretic trap adapted to separate target materials from other materials in a flow containing the target materials and other materials. The dielectrophoretic trap is adapted to be placed in series to the flow and/or in parallel to the flow with direct current and/or alternating voltage or combinations of direct current and alternating voltage. An electrode system including a first electrode and a second electrode is provided in the dielectrophoretic trap. When an electrical voltage is applied to the first electrode and the second electrode a dielectrophoretic force is created between the first electrode and the second electrode. The first electrode and the second electrode are shaped and positioned relative to each other so that that the areas where said dielectrophoretic force zeros between said first electrode and said second electrode is a minimum.
Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description and by practice of the invention.